Digital Rights Management (DRM) refers to techniques that are used to protect content, such as by controlling or restricting the use of digital media content on electronic devices. One characteristic of DRM is that it can bind the media content to a given machine or device. Thus, a license that pertains to a particular piece of content and that defines rights and restrictions associated with the piece of content will typically be bound to the given machine or device. As a result, a user may not take the piece of content and move it to another machine in order to playback the content.
Current DRM techniques have limitations. They are often compatible with only two types of protocols for transferring digital media—HTTP and RTSP. But other protocols may now or in the future be better suited for transferring digital media. Also, content protected by DRM may be limited to a particular content type. One particular content type—ASF files—permits only one set of rights and restrictions, i.e. “policies”, to apply to an entire ASF file. For example, when a video file is rendered, either Macrovision may be required to be enabled on an analog video output for the whole file, or it may not be required at all.